MR imaging of diffusion of 3He gas in healthy and diseased lungs

q‐space analysis of lung morphometry in vivo with hyperpolarized3He spectroscopy

“…In recent years, HHe diffusion-weighted imaging (DWI) has been used to assess the lung microstructure for the detection and characterization of emphysema. In emphysema, a disease characterized by tissue destruction and enlargement of lung alveoli, the measured HHe ADC is elevated relative to that of healthy adults (2,6,7). Histological studies in animal models of emphysema have correlated this elevation in ADC with increased alveolar size (8).…”

MRI of lungs using partial liquid ventilation with water‐in‐perfluorocarbon emulsions

“…Thus, the ADC may be used to detect damage to the lung architecture. It has been reported that the ADC of 3 He gas in emphysematous regions of lungs increases compared to that in healthy lungs (4). The measurement of diffusion in the lungs has obvious diagnostic value.…”

“…Rat lung can be modeled as a porous structure, a network of interconnected spherical compartments (alveoli) (4). Exchange between the compartments is assumed to be minimal.…”

“…The diffusion coefficient is an excellent contrast mechanism for lung imaging and sensitive evaluation of lung functions and diseases (4,25). It is based on a random translational motion of nuclei (e.g., protons in the aerosol water) in the lungs.…”

“…A recent exciting development is the use of hyperpolarized 129 Xe (1) or 3 He (2)(3)(4)(5). However, the expense of the required laser optical pumping facility, and the limited availability of 129 Xe and 3 He limit its potential applications.…”